Chlorophyll a and Phaeopigments were extracted with acetone 90% from freezed dried sediment following the method of Yentsch & Menzel (1963): A method for the determination of phytoplankton chlorophyll a and phaeophytin by fluorescence. Deep-Sea Res 10: 221-231. Chlorophyll a and Phaeopigments were measured with a Turner 700 fluorometre following Shuman and Lorenzen (1975): Quantitative degradation of chlorophyll by a marine herbivore, Limnology and Oceanography, 20.